This is from the American Health Association:

"Following a heart-healthy lifestyle can lower your chances of having a stroke, and it can also make a big difference in your mental abilities as you age.

In fact, getting plenty of physical activity, eating a healthy diet and other behaviors that strengthen your heart can have a profound effect on the way you think, how you act and what you remember.

“Most people don’t understand the connection between heart health and brain health, and as doctors we’re learning more every day,” said Ralph Sacco, M.D., chief of neurology at the Miller School of Medicine at the University of Miami and past president of the American Heart Association. “New studies have shown that the risk factors that can lead to heart disease and stroke, such as physical inactivity and obesity, also contribute to dementia, Alzheimer’s disease, memory loss and cognitive dysfunction.”

Here’s what happens: Those unhealthy behaviors can lead to narrowing of the blood vessels. That reduces blood flow to the brain, and leads to hardening of the arteries of the heart and the brain.

When your brain doesn’t get the blood flow it needs, it can begin to malfunction. As a result, Sacco said, you could experience problems thinking, trouble with memory, difficulty finding your way from place to place and deterioration in cognitive function."